San Francisco App Showcase
via datasf.org
San Francisco has a showcase of applications using open data. And I've featured London's before here, too. San Francisco has got lots of interesting and useful apps, including one I've been wanting for ages but which there just isn't the open data for yet.
Maybe every city should have one these showcases - letting citizens know what's on offer and highlighting the work of local (and perhaps not so local) developers. And maybe that's the kind of thing we can expose through the Knowledge Hub, too.